Active prices have neither a priceType nor a validForMemberTier property.
Strikethrough prices set the priceType property to StrikethroughPrice (for a transition period, ListPrice is also allowed) and cannot have a validForMemberTier property.
Member prices are marked with a validForMemberTier property and cannot have a priceType property.
Active price. The active price is the price at which the product is currently offered.
Strikethrough price. The strikethrough price is the the price during a sale, the higher regular price at which the product is normally offered. It may be displayed as a struck-through price to draw attention to a lowered active price.
Why we care. If you offer member loyalty pricing, then this beta is something you may want to give a try. If you want to better understand the various pricing types offered in this structured data, you should review the Merchant listing structured data guidelines again.